One of the more popular developments in floor coverings in recent years is the individual precut backed carpet tile, usually of a size comparable to more traditional types of tiles such as linoleum. Carpet tiles provide flexibility in designing and obtaining floor coverings where the performance and appearance of carpet are desired, but where traditional roll or area carpeting may not be appropriate because of cost, flexibility, area geometry or other factors.
Prior to the development of tiles having the various characteristics desirably found in carpeting such as durability and appearance, carpeting choices were generally limited to area rugs or wall-to-wall carpeting formed from single pieces or rolls of carpet. Area rugs are of certain definite sizes and consequently may only be used in certain types of areas. Similiarly, regular roll or wall-to-wall type carpeting must be customized to fit the areas in which it is to be used. In contrast, the carpet tile provides a more efficient method of obtaining carpeting both on areas which are traditionally difficult to carpet and on those which have traditionally been carpeted with area rugs or wall-to-wall carpets. Carpet tiles can be easily laid individually in column by row arrays, and only the carpet tiles which border the edges of the area to be carpeted need be customized. Either wall-to-wall or definite areas of carpeting may be accomplished. Similarly, replacement of worn and damaged tiles can be done in limited areas.
A desirable carpet tile will exhibit the necessary qualities with respect to both function and appearance which are desirably required of other types of carpeting.
A carpet tile generally comprises some sort of primary backing, to which the fibers, tufts or loops forming the carpet face are attached. Functionally, because individual carpet tiles are relatively small, e.g. 18".times.18", they are also relatively light in weight and individually do not have the amount of inertial weight that an entire piece of area or wall-to-wall carpet would have, and which helps maintain the carpet in a flat orientation. Consequently, the carpet tile must have some additional backing characteristics enabling it to lay flat of its own accord, rather than as a result of being a small portion of a much larger heavier carpet held flat by its own weight. Because of their small size and weight, most carpet tile is backed after weaving or tufting with an impermeable backing of resilient material, such as PVC, polyurethane or the like, which provides added stiffness and weight and which helps the carpet tile lay flat by itself.
Preferably, carpet tile is formed by die cutting smaller tile size sections from previously woven, tufted or fiber bonded carpet. For example, tile may be formed by tufting yarns through a permeable primary backing to form a length or roll of carpet of a given width, e.g. 3, 9 or 12 feet. The surface of the primary backing opposite to the tufts forming the carpet face may then have resilient material such as latex, polyvinyl chloride (PVC), foam, etc. coated thereon or otherwise applied thereto, after which the backed carpet fabric is cut into the desired dimensions for individual tiles.
For the sake of appearance, a carpet carrying one or more designs is often desirable. When area carpets or roll carpets are manufactured, they may be either woven with multiple colors of yarn, or printed or dyed after weaving to produce desired designs. In a similar manner, where carpeting is formed from carpet tiles, a design which may be either repetitive from tile to tile or which builds from tile to tile into a larger design is also sometimes desirable.
Certain difficulties arise, however, in the production of carpet tiles carrying designs. First, where patterned carpet tiles are cut from larger portions of patterned carpet, the cutting process can distort the pattern. In such cases, a desired pattern formed from the cut tiles cannot be reproduced from carpet to carpet and often the original pattern of the larger carpet from which the carpet tiles were cut cannot be accurately recreated. Moreover, where the pattern design repeat is larger than any individual tile, the distorted tiles make difficult the orientation of individual tiles to create or recreate a pattern.
There exist other problems in obtaining individual carpet tiles carrying precisely and accurately reproduced patterns. For example, one method of printing carpet tiles to get precise and accurate pattern repetition is the screen stenciling process. In this process, used to color many textile items, individual carpet tiles are moved past a screen stencil, often in the form of a roller. Colorant is applied through predetermined portions of the screen onto corresponding portions of the surface of the carpet tile. While good pattern repetition may be obtained by screen stenciling, those familiar with screen stenciling will be aware that this method generally provides only a surface coloring of deeper pile fabrics such as carpet tufts. When only the upper surfaces of the tufts of the carpet tiles are so colored, several problems arise. First, because of the lack of color in the lower portions of the tufts, the surface colored tufts can give an unpleasant appearance when movement or traffic causes them to become moved. Second, such surface coloring will often wear faster than will the carpet itself, resulting in a shorter lifetime of the desired pattern.
In coloring portions of carpeting of larger, traditional sizes, certain methods have been proposed for avoiding some of the limitations of screen stencil printing. In particular the use of a tuft dye mold has been used in coloring pile fabrics such as tufted carpets. A tuft dye mold generally comprises a horizontal mold of a size corresponding to the article of tufted fabric to be colored. The horizontal mold is divided into various sections corresponding to the pattern of color desired on the final object by a number of vertical walls within the horizontal mold. The various walls serve to separate various sections of the mold from each other and to separate corresponding sections of the pile fabric from one another when brought into contact therewith. In printing a tufted fabric, the tufted fabric is either first brought in contact with the mold followed by the addition of fluid colorant to the individual sections, or colorant may be added first following which the tufted fabric is moved into engagement with the mold. In either case, the vertical divider walls between respective colorant-containing sections serve two purposes: they slip through the tufts of the fabric and provide definite lines of demarkation between respective portions of the tufted fabric, and they provide a barrier to the flow of colorant preventing it from migrating from one respective portion of the tufted fabric to another. Ideally, coloring using a tuft-dye mold produces color along the entire length of the carpet tuft, resulting in a rich appearance in the pattern which will remain visible for the life of the carpet, regardless of wear. Typical methods and devices for attempting such printing on large roll and/or piece carpeting include those described in U.S. Pat. Nos. 4,031,280; 3,175,488; 2,984,540; and 2,816,811.
With regard to individual, backed carpet tiles, however, problems arise in tuft dye mold printing which are not of concern in printing larger pieces of carpet, but which have heretofore prevented its use on backed carpet tiles. Basically, as set forth earlier herein, larger pieces of carpet have primary backings of permeable material. When such a carpet is printed using a tuft dye mold, the woven backing provides a fluid-permeable surface through which colorant may flow whenever there is an excess of colorant in any one or more of the respective portions of the tuft dye mold. Since at this stage the carpet has not yet received a resilient backing excess color will flow through the primary backing rather than migrating into adjacent pattern areas. Because of this safety zone provided by the permeable backing, excess colorant is easily prevented from flowing into non-designated areas and is thus prevented from spoiling the appearance of the pattern.
In coloring carpet tile, after it has been cut and backed, there is no "safety zone" into which excess colorant can flow because of the impermeable resilient backing. Consequently, excess colorant tends to migrate between various sections of the carpet, even forcing its way past the vertical barriers in the tuft dye mold. This may result in a carpet tile with poor color resolution between adjacent colored areas and an undesirable final appearance.
Additionally, the tuft dye mold printing processes developed for large carpets tend to be most suitable for low viscosity, highly fluid colorants the placement of which, while satisfactory enough for larger patterns on larger carpets, cannot be controlled with the accuracy and precision required to reproduce a pattern on the much smaller scale of a carpet tile.
Finally, where the face portion of the carpet is of the "level loop" type, previous attempts to accomplish tuft dye mold printing have been unsuccessful on carpets of all sizes because of the difficulty in controlling the flow of colorant on, around and through the loops.
It is thus an object of the present invention to provide a method by which individual backed carpet tiles may be both accurately and precisely colored so that any carpet pattern formed from these tiles will be of the desired final pattern regardless of the order in which the individual tiles were printed.
It is another object of the present invention to provide a method of coloring individual precut backed carpet tiles in a tuft dye mold while producing colorant penetration along the entire length of the tufts, whether cut pile or loops, along with high resolution and definition of colored portions of the carpet tile.